Use pooled array for header names

Author: benaadams

src/Microsoft.AspNet.Server.Kestrel/Http/Frame.cs

@@ -188,7 +188,7 @@ public async Task RequestProcessingAsync()
                         }
                     }
 
-                    while (!terminated && !_requestProcessingStopping && !TakeMessageHeaders(SocketInput, _requestHeaders))
+                    while (!terminated && !_requestProcessingStopping && !TakeMessageHeaders(SocketInput, _requestHeaders, Memory2))
                     {
                         terminated = SocketInput.RemoteIntakeFin;
                         if (!terminated)
@@ -697,12 +697,7 @@ private bool TakeStartLine(SocketInput input)
             }
         }
 
-        static string GetString(ArraySegment<byte> range, int startIndex, int endIndex)
-        {
-            return Encoding.UTF8.GetString(range.Array, range.Offset + startIndex, endIndex - startIndex);
-        }
-
-        public static bool TakeMessageHeaders(SocketInput input, FrameRequestHeaders requestHeaders)
+        public static bool TakeMessageHeaders(SocketInput input, FrameRequestHeaders requestHeaders, MemoryPool2 memorypool)
         {
             var scan = input.ConsumingStart();
             var consumed = scan;
@@ -762,6 +757,7 @@ public static bool TakeMessageHeaders(SocketInput input, FrameRequestHeaders req
                     scan = beginValue;
 
                     var wrapping = false;
+
                     while (!scan.IsEnd)
                     {
                         if (scan.Seek('\r') == -1)
@@ -792,16 +788,24 @@ public static bool TakeMessageHeaders(SocketInput input, FrameRequestHeaders req
                             continue;
                         }
 
-                        var name = beginName.GetArraySegment(endName);
-                        var value = beginValue.GetString(endValue);
-                        if (wrapping)
+                        var block = memorypool.Lease(MemoryPool2.DefaultBlockLength);
+                        try
                         {
-                            value = value.Replace("\r\n", " ");
-                        }
+                            var name = beginName.GetArraySegment(endName, block.Data);
+                            var value = beginValue.GetString(endValue);
+                            if (wrapping)
+                            {
+                                value = value.Replace("\r\n", " ");
+                            }
 
-                        consumed = scan;
-                        requestHeaders.Append(name.Array, name.Offset, name.Count, value);
-                        break;
+                            consumed = scan;
+                            requestHeaders.Append(name.Array, name.Offset, name.Count, value);
+                            break;
+                        }
+                        finally
+                        {
+                            memorypool.Return(block);
+                        }
                     }
                 }
                 return false;

src/Microsoft.AspNet.Server.Kestrel/Infrastructure/MemoryPoolIterator2.cs

@@ -566,7 +566,7 @@ public string GetString(MemoryPoolIterator2 end)
             }
         }
 
-        public ArraySegment<byte> GetArraySegment(MemoryPoolIterator2 end)
+        public ArraySegment<byte> GetArraySegment(MemoryPoolIterator2 end, ArraySegment<byte> scratchBuffer)
         {
             if (IsDefault || end.IsDefault)
             {
@@ -578,9 +578,18 @@ public ArraySegment<byte> GetArraySegment(MemoryPoolIterator2 end)
             }
 
             var length = GetLength(end);
-            var array = new byte[length];
-            CopyTo(array, 0, length, out length);
-            return new ArraySegment<byte>(array, 0, length);
+
+            if (length < scratchBuffer.Count)
+            {
+                CopyTo(scratchBuffer.Array, scratchBuffer.Offset, length, out length);
+                return new ArraySegment<byte>(scratchBuffer.Array, scratchBuffer.Offset, length);
+            }
+            else
+            {
+                var array = new byte[length];
+                CopyTo(array, 0, length, out length);
+                return new ArraySegment<byte>(array, 0, length);
+            }
         }
 
         public MemoryPoolIterator2 CopyTo(byte[] array, int offset, int count, out int actual)

test/Microsoft.AspNet.Server.KestrelTests/FrameTests.cs

@@ -56,11 +56,13 @@ public void EmptyHeaderValuesCanBeParsed(string rawHeaders, int numHeaders)
             Buffer.BlockCopy(headerArray, 0, inputBuffer.Data.Array, inputBuffer.Data.Offset, headerArray.Length);
             socketInput.IncomingComplete(headerArray.Length, null);
 
-            var success = Frame.TakeMessageHeaders(socketInput, headerCollection);
-
-            Assert.True(success);
-            Assert.Equal(numHeaders, headerCollection.Count());
+            using (var memorypool = new MemoryPool2())
+            {
+                var success = Frame.TakeMessageHeaders(socketInput, headerCollection, memorypool);
 
+                Assert.True(success);
+                Assert.Equal(numHeaders, headerCollection.Count());
+            }
             // Assert TakeMessageHeaders consumed all the input
             var scan = socketInput.ConsumingStart();
             Assert.True(scan.IsEnd);